1. Field of the Invention
The present invention concerns atmospheric gas burners, of the hyperstoichiometric mixture type of a substantially tubular shape, in which it is arranged that the mixture discharges from a series of slots made in the top surface of the burner body, these slots being arranged in one or more rows, which run parallel to the burner axis.
2. Description of the Prior Art
Burners have been known for some time which operate by hyperstoichiometric combustion; some of these burners moreover have provision for surface cooling, for example by means of the boiler water, all with the main aim of reducing the NO.sub.x content in the combustion products.
Burners of such a type are described, for example, in Italian patents nos, 1,191,596 and 1, 214,314 in the same name as the present applicant.
The utilisation of cooling water, generally taken from the boiler circuit, allows the burners optimum possibilities of use, by utilising all the gases available in the distribution system, in particular permitting them to function even in the presence of extremely low pressures in the aforesaid systems.
In fact until quite recently the occurrence of even sudden pressure drops was not rare.
Nowadays distribution controls are much improved and one can be reasonably certain of being able to count on pressures at the injector of 120-140 mm water column, at least as regards natural gas.
This allows, on the one hand, for a pressure to be arranged, sufficient in every case to obtain the hyperstoichiometric mixture without having to resort to special measures and, on the other, of being able to vary the pressure, for example, from 100 to 140 mm, thus allowing a certain modulation of the load.